KR102001496B1 - Infrared ray shielding multi-layer film - Google Patents

Abstract

The infrared blocking multilayer film according to the embodiment not only blocks infrared rays in a wider area, but also has a high blocking ratio in the near infrared region, and thus has excellent heat energy blocking efficiency. Therefore, it can be applied as an infrared ray blocking film for buildings, automobile exterior glass, etc., so that it is possible to save energy by reducing air conditioning consumption in summer or by preventing loss of heating heat in winter.

Description

[0001] INFRARED RAY SHIELDING MULTI-LAYER FILM [0002]

The present invention relates to an infrared ray blocking multilayer film applicable to buildings, automobile exterior glass, and the like.

Recently, several films have been proposed that lower the room temperature by blocking the heat energy coming from the sun.

For example, a method of manufacturing a film using a material that absorbs light in a specific region of infrared rays, and attaching the produced film to a glass surface to block heat energy has been proposed. However, when the infrared blocking rate is increased, these films also block the light in the visible light region, thereby causing visibility problems. In addition, since most of the infrared rays absorb light, there is a problem that the temperature of the film or glass is increased and the heat efficiency of the heat sink is lowered.

To solve this problem, recently, films with less visible light reflection and high infrared ray blocking efficiency have been developed. For example, Korean Unexamined Patent Publication No. 2007-0073753 discloses a resin composition comprising a single resin layer such as polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), and polyethylene naphthalate, or a reflective layer and a protective layer Discloses a multilayer film. Korean Unexamined Patent Publication No. 2011-0089770 discloses a multilayer film composed of a reflective layer and a protective layer in which a single resin layer such as PET, polyethylene, polyester, polylactic acid, or mixed resin layers are laminated.

As such, various infrared blocking technologies are continuously being developed to increase energy efficiency, and the demand for increasing energy efficiency is increasing.

Korean Laid-Open Patent Publication No. 2012-0073753 Korean Patent Laid-Open Publication No. 2011-0089770

Therefore, in the embodiment, the transmittance in the visible light region is maintained at a certain level to ensure the visibility, while the infrared transmittance, which can reduce the energy consumption by lowering the indoor temperature by intercepting the wavelength of the infrared region, Provide high film.

The embodiment has a structure in which a reflective layer in which a first resin layer and a second resin layer are alternately stacked and a protective layer formed on both surfaces of the reflective layer, wherein the reflective layer and the protective layer are coextruded and laminated, (M = Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn) in which the near infrared absorber contains a near infrared absorber and the near infrared absorber is WOx (2.45? X? 2.999) , Al, and Cu, 0.1? Y? 3, 1? Z? 15), or a mixture thereof.

Further, in the embodiment, the first resin layer composition containing a polyester resin is melted at 250 to 300 DEG C, the second resin layer composition containing the acrylic resin is melted at 200 to 250 DEG C, and a polyester resin, a near infrared absorber , A dispersion stabilizer and a surfactant is melted at a temperature of 250 to 300 DEG C, and then a first resin layer and a second resin layer are alternately laminated to form a reflection layer, and a protective layer is formed on both surfaces of the reflection layer And then pneumatically delivering the compositions to the infrared shielding multilayer film.

The infrared-shielding multilayer film according to the embodiment can block infrared rays in a wider area, and in particular, has a high blocking ratio in the near-infrared region, and thus has excellent thermal energy shielding efficiency. In addition, the light transmittance in the visible light region is high and the visibility is excellent. Therefore, it can be applied as an infrared ray blocking film for buildings, automobile exterior glass, etc., so that it is possible to save energy by reducing air conditioning consumption in summer or by preventing loss of heating heat in winter.

1 is a cross-sectional view of an infrared blocking multilayer film according to an embodiment.
FIG. 2 is a graph showing transmittances of the multilayer films prepared in Examples 1 to 3 by wavelength. FIG.
FIGS. 3 and 4 are graphs showing transmittances of the single layer and multilayer films prepared in Comparative Examples 1 to 4 according to wavelengths.

The embodiment has a structure in which a reflective layer in which a first resin layer and a second resin layer are alternately stacked and a protective layer formed on both surfaces of the reflective layer, wherein the reflective layer and the protective layer are coextruded and laminated, (M = Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn) in which the near infrared absorber contains a near infrared absorber and the near infrared absorber is WOx (2.45? X? 2.999) , Al, and Cu, 0.1? Y? 0.5, and 2.2? Z? 3.0), or a mixture thereof.

Protective layer

The protective layer may comprise tungsten oxide as a near infrared absorber. Specifically, the protective layer may include a near-infrared absorbent that is a fine particle represented by WOx, a fine particle represented by MyWOz, or a mixture thereof, wherein x is from 2.45 to 2.999, y is from 0.1 to 3, Z is 1 to 15 and M is at least one selected from the group consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al and Cu. More specifically, the fine particles may be CsWO ₃ , LiWO ₃ , RbWO _{3 ,} AlWO _3, or the like. Further, the fine particles may have an average particle diameter of 1 to 800 nm, 50 to 600 nm, 50 to 500 nm, or 70 to 300 nm.

The near infrared absorbing agent may be contained in an amount of 0.1 to 10% by weight, 0.1 to 5% by weight, or 1 to 3% by weight based on the total weight of the protective layer. When it is within the above range, it is excellent in energy saving and economical efficiency because it has excellent near-infrared ray shielding effect. Further, the haze of the film can be adjusted to 5% or less, which is superior in transparency.

The protective layer may further comprise a polyester resin, a dispersion stabilizer, and a surfactant.

The polyester resin may be a prepolymer. The term "prepolymer" generally means a polymer having a relatively low molecular weight in which a degree of polymerization is stopped at an intermediate stage so as to facilitate molding in the production of a final molded product. The prepolymer can be formed by reacting with a single polymerizable compound or with another polymerizable compound.

The weight average molecular weight (Mw) of the polyester resin may be 40 to 70 g / mol, for example 45 to 70 g / mol, for example 55 to 65 g / mol.

The polyester resin may be one prepared by esterifying a diol compound and a dicarboxylic acid compound.

The diol compound used in the production of the polyester resin is, for example, ethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propanediol, 1,2-octanediol, Butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) 1,3-propanediol, 2,2-diethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl- -Dimethyl-1,5-pentanediol, spiroglycol, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane ) And diethylene glycol (2- (2-hydroxyethoxy) ethan-1-ol).

Examples of the dicarboxylic acid compound used in the production of the polyester resin include aromatic dicarboxylic acids such as terephthalic acid, dimethylterephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and orthophthalic acid; Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid; Alicyclic dicarboxylic acid; Esters thereof; And mixtures thereof.

 The protective layer may contain the polyester resin in an amount of 40 to 70 wt%, or 55 to 65 wt%.

The dispersion stabilizer may include 1,1-dichloroethane, potassium hydroxide, sodium hydroxide, adipic acid salt compounds, amide compounds or a mixture thereof. Specifically, the dispersion stabilizer is selected from the group consisting of 1,1-dichloroethane, potassium hydroxide, sodium hydroxide, poly (1,6-hexamethylene adipate), N, N'- N, N'-dibenzyl-1,6-diaminohexane, or a mixture thereof. More specifically, the dispersion stabilizer is selected from the group consisting of 1,1-dichloroethane, potassium hydroxide, sodium hydroxide, poly (1,6-hexamethylene adipate), N, N'- dibenzyl-1,6-diaminohexane, .

More specifically, the dispersion stabilizer may comprise 1 to 20% by weight of 1,1-dichloroethane, 1 to 20% by weight of potassium hydroxide, 1 to 20% by weight of sodium hydroxide, 1 to 20% Methylene adipate) and / or N, N'-dibenzyl-1,6-diaminohexane in an amount of 20 to 60% by weight.

The poly (1,6-hexamethylene adipate) may have a number average molecular weight (Mn) of 100 to 10,000 g / mol. Specifically, the poly (1,6-hexamethylene adipate) may have a number average molecular weight of 1,000 to 10,000 g / mol, 1,000 to 7,000 g / mol, or 1,000 to 5,000 g / mol.

The protective layer may contain the dispersion stabilizer in an amount of 0.1 to 30% by weight, or 0.5 to 30% by weight, based on the total weight.

The surfactant may include sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecylnaphthalenesulfate, sodium hexylbenzenesulfonate, citric acid, or mixtures thereof. Specifically, the surfactant may include sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecylnaphthalenesulfate, sodium hexylbenzenesulfonate, citric acid, and the like. More specifically, the surfactant may comprise, based on its total weight, 10 to 50 wt% sodium dodecylsulfate, 10 to 40 wt% sodium dodecylbenzenesulfonate, 1 to 20 wt% sodium dodecylnaphthalenesulfate, 1 to 20% by weight of benzenesulfonate, and / or 10 to 50% by weight of citric acid.

Further, the protective layer may contain the surfactant in an amount of 5 to 50 wt%, or 5 to 30 wt%, based on the total weight.

The protective layer may have a thickness of 5 占 퐉 to 50 占 퐉, 5 占 퐉 to 30 占 퐉, or 5 占 퐉 to 10 占 퐉. The protective layer may be composed of a highly dispersed polyester resin obtained by polymerizing a mixed composition comprising the polyester resin, the dispersion stabilizer, the surfactant, and the near infrared absorber. At this time, the highly disperse polyester resin may have an intrinsic viscosity of 0.35 dl / g to 1.50 dl / g, or 0.50 dl / g to 0.80 dl / g. When the refractive index is within the above range, the refractive index is maintained at an appropriate level, and the wavelength of infrared rays, particularly near-infrared rays, can be effectively absorbed.

Reflective layer

The reflective layer may be in the form of a laminate in which the first resin layer and the second resin layer are alternately laminated. Further, the reflective layer may be in the form of being uniaxially and / or stretched in the biaxial direction.

The first resin layer may include a polyester resin, and the second resin layer may include an acrylic resin. Specifically, the first resin layer may include a polyethylene terephthalate (PET) resin, and may further include silica particles for improving the winding property. Further, the second resin layer may be a polymethyl methacrylate (PMMA) alone resin.

One layer of the first resin layer may have a thickness of 130 nm to 200 nm, and one layer of the second resin layer may have a thickness of 150 nm to 250 nm. When the thickness is within the above range, it is possible to efficiently reflect light. At this time, the first resin layer and the second resin layer may each have a thickness gradient gradually increasing in a thickness direction of the reflective layer. Specifically, in the case of the first resin layer, the difference between the minimum thickness and the maximum thickness may be 13 to 20 nm, and in the case of the second resin layer, the difference between the minimum thickness and the maximum thickness may be 15 to 25 nm. The thickness gradient can be controlled by stretching. Specifically, the first resin layer and the second resin layer may be adjusted to various thicknesses by stretching to have a thickness gradient, from which the refractive indexes of the respective layers are different. The refractive index difference between the first resin layer and the second resin layer can cause optical interference that selectively reflects or transmits light of a specific wavelength, and can exhibit reflection characteristics. Further, by controlling the stretching direction and the stretching ratio, it is possible to exhibit a polarization characteristic that reflects only light in a certain direction.

The reflective layer including the first resin layer and the second resin layer may be stacked in a total of 150 layers or less, 100 layers or less, 50 to 150 layers, or 50 to 100 layers.

At this time, the first resin layer and the second resin layer may have a difference in inter-layer refractive index depending on the total lamination number. Specifically, when the total number of laminated layers of the first resin layer and the second resin layer is 100 layers or less, the refractive index difference between the first resin layer and the second resin layer is 0.25 to 0.50, or 0.25 to 0.35, Wherein the first resin layer and the second resin layer have a refractive index difference of 0.15 to 0.50 or 0.15 to 0.35 when stacked from 100 to 200 layers, And the refractive index difference between the second resin layers may be 0.12 to 0.50, or 0.12 to 0.35. When the refractive index difference between the first resin layer and the second resin layer is within the above-mentioned range, the refractive index difference between the first resin layer and the second resin layer can be appropriately adjusted, and the wavelength of infrared rays, particularly near infrared rays, can be effectively reflected.

Further, the polyester resin of the first resin layer and the acrylic resin of the second resin layer may have an intrinsic viscosity ratio of 1: 2 to 10, or 3 to 8. When the thickness is within the above range, the adhesion between the first resin layer and the second resin layer is improved and the laminated state can be maintained even after curing.

The film may further comprise a metal oxide layer on the outer surface of the protective layer for imparting conductivity. The metal oxide layer may include, but is not limited to, antimony tin oxide (ATO), indium tin oxide (ITO), tungsten oxide, or a mixture thereof.

The metal coating layer may be coated by an in-line coating, a gravure coating, or the like through a conventional adhesive.

The film may have an average transmittance of at least 50%, at least 60%, or from 50 to 70% in the visible light region at a wavelength of 400 to 780 nm. In addition, the film may have an average transmittance of less than 50%, or less than 40% in the infrared region of 800 to 2,000 nm, or 800 to 1,800 nm. Furthermore, the film can effectively block wavelengths in the (near) infrared region, with a blocking ratio of 90% or more or 95% or more in the near infrared region of 950 nm.

Further, the film may have an average transmittance in the visible light region of 50% or more, or 50 to 70%.

The infrared ray blocking film may have a b * value of -1.5 to 1.7 in an L * a * b * color system.

In addition, the film may have a haze of 5% or less, 3% or less, or 1.5% or less.

The embodiment is characterized in that the first resin layer composition containing a polyester resin is melted at 250 to 300 DEG C, the second resin layer composition containing an acrylic resin is melted at 200 to 250 DEG C, and a polyester resin, a near infrared absorber, A stabilizer and a surfactant is melted at a temperature of 250 to 300 DEG C and then a first resin layer and a second resin layer are alternately laminated to form a reflection layer and a protective layer is formed on both surfaces of the reflection layer, Lt; RTI ID = 0.0 > infrared-shielding < / RTI > multilayer film comprising pneumatically releasing the compositions.

The embodiment can be made into a multilayer film by melting and then co-extruding the compositions of the first resin layer, the second resin layer and the protective layer as described above.

Specifically, the protective layer can be produced by adding a dispersion stabilizer, a surfactant, and a near infrared absorbing agent to the prepolymer and heating and polymerizing. Specifically, by adding a near infrared absorber during polymerization of the polyester resin to increase the degree of dispersion, a polyester resin having a high transmittance of visible light and a high rate of blocking of light in the near infrared region can be produced.

The polyester resin, the dispersion stabilizer, the surfactant, and the near infrared ray absorbent are as described above.

A PET resin as a first resin layer and a PMMA resin as a second resin layer are melted in respective extruders and co-extruded to form a first resin layer and a second resin layer alternately And a protective layer is formed on both sides of the reflective layer.

As described above, the infrared-shielding multilayer film according to the embodiment can shield infrared rays in a wider area, and particularly has a high blocking ratio in the near-infrared region, and thus has excellent thermal energy shielding efficiency. In addition, the light transmittance in the visible light region is high and the visibility is excellent. Therefore, it can be applied as an infrared ray blocking film for buildings, automobile exterior glass, etc., so that it is possible to save energy by reducing air conditioning consumption in summer or by preventing loss of heating heat in winter.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are intended to illustrate the present invention, but the scope of the present invention is not limited thereto.

[ Example ]

Manufacturing example  1: Preparation of protective layer composition

1,000 g of terephthalic acid (TPA) and 550 g of ethylene glycol (EG) were mixed and esterified at a temperature of about 170 캜 for about 20 hours to prepare a prepolymer (polyester resin). Thereafter, 430.6 g of a dispersion stabilizer, And y is 1 to 2, z is 1 to 10, and average particle diameter is 272.2 nm), and a near infrared ray absorbing agent (manufactured by KANPI NANO, product name: ANP-TF, chemical formula: CsyWOz, Were added and mixed with stirring.

Examples of the dispersion stabilizer include 1,1-dichloroethane, potassium hydroxide, sodium hydroxide, poly (1,6-hexamethylene adipate) (number average molecular weight: about 3,800 g / mol) and N, N'- , 6-diaminohexane in a weight ratio of 1: 1: 1: 3: 4 was used. Also, a mixture containing sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecylnaphthalenesulfate, sodium hexylbenzenesulfonate and citric acid in a weight ratio of 3: 2: 1: 1: 3 was used as the surfactant Respectively. The mixed composition was polymerized at 275 캜 for 3 hours to prepare a highly dispersed polyester resin (weight average molecular weight: 35,000 g / mol, intrinsic viscosity (IV): 0.68 dl / g).

Manufacturing example  2: Preparation of first resin layer composition

PET resin (SKC, intrinsic viscosity of 0.8 dl / g) was used as the first resin layer.

Manufacturing example  3: Preparation of second resin layer composition

PMMA resin (IF870S, LG MMA) was used as the second resin layer. At this time, the melt flow index of the PMMA resin is 24.0 g / 10 min.

Example  1: Preparation of infrared ray blocking multilayer film

The protective layer composition, the first resin layer composition and the second resin layer composition prepared above were dried using a conventional dehumidifying dryer and a paddle dryer, respectively, and then supplied to three extruders, respectively. The protective layer composition was melted at 280 占 폚, the first resin layer was melted at 280 占 폚, and the second resin layer was melted at 230 占 폚. Then, it was supplied to a feed block for multi-layer formation. The first resin layer composition fed into the multilayer forming block was divided into 71 layers and the second resin layer was divided into 72 layers so that the first resin layer and the second resin layer were alternately laminated. Specifically, the thickness of one layer of the first resin layer was 135 to 166 nm, and each layer was continuously changed within the above-mentioned range to make a total of 71 layers. The thickness of one layer of the second resin layer was 150 to 160 nm, and the total thickness of the first resin layer and the second resin layer was 35 mu m Respectively. At this time, each time the first resin layer and the second resin layer were alternately stacked, the thickness was increased by an initial thickness (DELTA dx1 / number of layers) so that a thickness gradient was formed. At this time, Δd is the difference between the interlayer thicknesses.

A protective layer having a thickness of 7.5 mu m was disposed on both sides of the laminate of the 143 layers (first resin layer + second resin layer), and the multilayer film of 145 layers was co-extruded to form an infrared blocking multilayer film .

Example  2 and 3: Infrared Blocking multilayer  Production of film

An infrared blocking multilayer film was produced in the same manner as in Example 1 except that the content of the near infrared absorber was changed as shown in Table 1 below.

Comparative Example  1 to 3: Reflective layer  Manufacture of single layer film not containing

A single layer film having a thickness of 30 占 퐉 was prepared using the protective layer composition of Preparation Example 1, except that the content of the near infrared absorbing agent was changed as shown in Table 2, To prepare a single-layer film containing no reflective layer.

Comparative Example  4: Preparation of multilayer film without protective layer

Except that the first resin layer composition and the second resin layer composition of Production Examples 2 and 3 were used to produce a film having a thickness of 35 탆, Was prepared.

Test Example 1: 950 nm Having a wavelength  Blocking rate of light ( % )

For the films of Examples 1 to 3 and Comparative Examples 1 to 4, the blocking ratio of light having a wavelength of 950 nm was measured with SD2400 manufactured by EDTM.

Test Example  2 : Hayes ( % )

The films of Examples 1 to 3 and Comparative Examples 1 to 4 were cut into a size of 210 mm x 297 mm x 25 m (width x length x thickness), and the film was dyed at 25 DEG C using an NDH-5000W haze meter according to the ASTM D 1003 method The haze was measured.

Test Example 3: L * a * b * Color system

Colors of the films of Examples 1 to 3 and Comparative Examples 1 to 4 were measured using a spectrophotometer (manufacturer: HunterLab, model name: UltraScan Pro).

Test Example 4: UV blocking rate, visible light average transmittance and ultraviolet-visible light spectrum

UV-VIS spectra of the films of Examples 1 to 3 and Comparative Examples 1 to 4 were measured using UV-2450 from SHIMADZU. The results are shown in Table 1 and Fig.

As shown in Tables 1 to 3 and Figs. 1 to 3, the infrared-shielding multilayer films of Examples 1 to 3 had a transmittance of visible light in a range of 400 to 780 nm of 50% or more, transmittance of infrared rays in a region of 800 to 2,000 nm It was confirmed that the transmittance at a near infrared ray wavelength of 50% or less, especially 950 nm, was close to 0%. On the other hand, in the films of the single layer not including the reflective layer of Comparative Examples 1 to 3 and the film not including the protective layer of Comparative Example 4, the result of at least one of the blocking factor, the chromaticity meter and the haze in the near- Respectively.

110 (111, 112): protective layer
120: reflective layer
121: first resin layer
122: second resin layer

Claims (20)

A reflective layer in which a first resin layer and a second resin layer are alternately laminated; And
And a protective layer formed on both sides of the reflective layer, wherein the reflective layer and the protective layer are co-extruded and laminated,
Wherein the protective layer comprises a polyester resin, a dispersion stabilizer, a surfactant and a near infrared absorber,
Wherein the protective layer comprises a highly dispersed polyester resin obtained by polymerizing a mixed composition comprising the polyester resin, the dispersion stabilizer, the surfactant and the near infrared absorbing agent,
Wherein the dispersion stabilizer comprises 1,1-dichloroethane, potassium hydroxide, sodium hydroxide, adipic acid salt compound, amide compound or a mixture thereof,
Wherein the near infrared absorber is at least one of MyWOz (M = Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al and Cu) represented by WOx (2.45? X? 2.999) , 0.1? Y? 3, 1? Z? 15), or a mixture thereof,
Wherein the highly dispersed polyester resin has an intrinsic viscosity of 0.35 dl / g to 1.50 dl / g,
An infrared blocking multilayer film having an average transmittance in the visible light region of 50 to 70% and a haze of 5% or less. The method according to claim 1,
Wherein the near infrared absorber is contained in an amount of 0.1 to 10% by weight based on the total weight of the protective layer. delete The method according to claim 1,
Wherein the protective layer comprises an amount of 40 to 70 wt% of the polyester resin, 0.1 to 30 wt% of a dispersion stabilizer, and 5 to 50 wt% of a surfactant. The method according to claim 1,
Wherein the protective layer has a thickness of 5 占 퐉 to 50 占 퐉. delete The method according to claim 1,
Wherein the first resin layer comprises a polyester resin and the second resin layer comprises an acrylic resin. 8. The method of claim 7,
The total number of laminated layers of the first resin layer and the second resin layer
The refractive index difference between the first resin layer and the second resin layer is 0.25 to 0.50,
A refractive index difference between the first resin layer and the second resin layer is 0.15 to 0.50 when the first resin layer and the second resin layer are laminated with 100 to 200 layers,
Wherein the refractive index difference between the first resin layer and the second resin layer is 0.12 to 0.50 when laminated over 200 layers. 8. The method of claim 7,
Wherein the polyester resin of the first resin layer and the acrylic resin of the second resin layer have an intrinsic viscosity ratio of 1: 2 to 10. 8. The method of claim 7,
The thickness of the first resin layer gradually increases as the thickness of the first resin layer increases,
Wherein the second resin layer has a thickness gradient that gradually increases as the thickness of the second resin layer increases. 11. The method of claim 10,
Wherein one layer of the first resin layer has a thickness of 130 to 200 nm and one layer of the second resin layer has a thickness of 150 to 250 nm. The method according to claim 1,
Wherein the reflective layer is laminated to 50 to 150 layers. The method according to claim 1,
Wherein the reflective layer is laminated to 50 to 100 layers. The method according to claim 1,
Wherein the film further comprises a metal oxide layer on an outer surface of the protective layer. 15. The method of claim 14,
Wherein the metal oxide layer comprises antimony tin oxide (ATO), indium tin oxide (ITO), tungsten oxide, or mixtures thereof. The method according to claim 1,
Wherein the infrared blocking region of the film is 800 to 1,800 nm. 17. The method of claim 16,
Wherein the film has a near infrared ray rejection ratio of 95% or more at 950 nm. delete delete The first resin layer composition containing a polyester resin is melted at 250 to 300 캜, the second resin layer composition containing an acrylic resin is melted at 200 to 250 캜, and a polyester resin, a near infrared absorbing agent, a dispersion stabilizer, After the protective layer composition comprising the activator is melted at 250-300 < 0 > C,
The method of claim 1, wherein the first resin layer and the second resin layer are alternately laminated to form a reflective layer, and pneumatically releasing the compositions to form a protective layer on both sides of the reflective layer.

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